With US President Barack Obama presiding, the UN Security Council unanimously approved a resolution Thursday aimed at ridding the world of nuclear weapons.
Russia, China and developing nations supported the US-sponsored measure, giving it global clout and strong political backing.
The resolution calls for stepped up efforts to prevent the spread of nuclear weapons, promote disarmament and "reduce the risk of nuclear terrorism."
Obama was the first American president to preside over a Security Council summit, gaveling the meeting into session and announcing that "the draft resolution has been adopted unanimously."
"The historic resolution we just adopted enshrines our shared commitment to a goal of a world without nuclear weapons," Obama said immediately after the vote. "And it brings Security Council agreement on a broad framework for action to reduce nuclear dangers as we work toward that goal."
Obama at Security Council (Photo: AFP)
Just one nuclear weapon set off in a major city could cause major destruction, Obama said.
He said the global effort would seek to "lock down all vulnerable nuclear materials within four years."
"This is not about singling out an individual nation," he said. "International law is not an empty promise, and treaties must be enforced."
"We will leave this meeting with renewed determination," Obama said.
UN Secretary-General Ban Ki-moon saluted the national leaders for joining in the unprecedented Security Council summit on nuclear arms.
"This is a historic moment, a moment offering a fresh start toward a new future," he said.
British Prime Minister Gordon Brown told the UN Security Council that the world should consider "far tougher sanctions" against Iran if it continues to seek a nuclear bomb.
'Iran committed to nuclear nonproliferation'
Iran denies it is seeking nuclear weapons, but it is defying UN Security Council resolutions ordering it to suspend enriching uranium.
"As evidence of its breach of international agreements grows, we must now consider far tougher sanctions together," Brown said at the Security Council summit chaired Obama.
French President Nicolas Sarkozy said he supported dialogue with Tehran but so far it had produced no results and Iran had continued to enrich uranium.
"There comes a time when stubborn facts will compel us to take a decision if we want a world without nuclear weapons," Sarkozy said after the Security Council passed the resolution.
Both leaders also spoke about North Korea's nuclear weapons program, saying it was violating international regulations.
"If we have the courage to affirm and impose sanctions together against those who violate resolutions of the Security Council, we will be lending credibility to our commitment towards a world with fewer nuclear weapons," Sarkozy said.
"Talk of a nuclear-free future is nice, but we are facing two immediate nuclear crises," said the French leader.
"Iran is violating the Security Council's resolutions right before our eyes. The international community has urged Iran to agree to talks (on its nuclear program) since 2005, but since then there has only been more uranium enrichment, more centrifuges and a declaration by Iran's leader (President Mahmoud Ahmadinejad) to a UN member state off the map," he said, referring to Israel.
Iran's UN mission issued a statement Thursday saying it is committed to nuclear nonproliferation but believes negotiations with interested parties will only be successful if "illegal demands" are dropped.
"The Islamic Republic of Iran reiterates its readiness to engage in serious and constructive negotiations with interested parties," the mission said in a statement following the UN Security Council debate over Tehran's nuclear program.
"At the same time, we believe that as a prerequisite for success in future negotiations, futile and illegal demands of the past years that have proven to be of no avail should be abandoned," the statement said.
Reuters contributed to the report